The inventive concept relates to a memory device, and more particularly, to a method of refreshing a memory device, whereby refresh power may be reduced.
A volatile memory device, such as dynamic random access memory (DRAM), performs a refresh operation to maintain stored data. DRAM performs auto-refresh to generate a refresh row address in response to a periodically externally received refresh command and refreshes a memory cell row corresponding to the refresh row address. Also, DRAM performs self-refresh upon entering a self-refresh mode in response to a self-refresh enter (SRE) command to refresh memory cell rows in response to a built-in timer in the self-refresh mode. When auto-refresh and self-refresh are performed with all-bank refresh (ABR) and the SRE command is frequently issued, refresh operations are often performed more frequently than is necessary for data retention. Accordingly, refresh time of the DRAM unnecessarily increases, refresh power consumption increases and the DRAM performance may be degraded.